Magnetic mixer



H. H. NEAL 2,466,468

April 5, 1949.

MAGNETIC MIXER Filed Dec. 2s, 1946 IN VEN TOR. /VE/u.

A TTORIVE Y Patented Awpr. 5, 1949 UNITED STATES PATENT OFFICE 2,i66,468 mamario MIXER Harry Herbert Neal, Los Angeles, Calif. Application December 23, 1946, Serial No. 718,033 4 Claims. (Cl. 259`108) This invention relates to devices for agitating liquids and more particularly to a magnetic mixer.

Certain mixing or stirring operations must be carried out under conditions wherein the temperature of the mix is maintained at a desired level and wherein there is no additional inclusion of air. An example of the former is in the ileld of photo developing, especially of color film where even a slight temperature rise deleteriously affects the results. In the latter instance, certain chemical mixing operations would vary the resultant mix should air be drawn into the solution.

Accordingly, the primary object of the present y invention is to provide a mixer which will function eiectively to stir or mix a solution without materially affecting the temperature thereof and which can be performed without inclusion of air.

Another object ot the invention is to provide a mixer, as indicated, which is magnetically operated to provide for complete physical dissociation of the motive means and the vessel which holds the solution being mixed.

Another object of the invention is to provide a magnetic mixer embodying a novel form of stirrer element so formed as to maintain a central position with respect to the magnet which drives it and having minimum frictional engagement with the vessel in which the mixing operation is performed.

My invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working positionv and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes one embodiment of the present invention, which is given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a vertical sectional view of a magnetic mixer embodying the present invention.

Fig. 2 is a broken plan view, partly in section, of the motive means thereof.

The magnetic mixer which is shown in the drawing comprises motive means 5, a vessel G containing a liquid solution to be stirred or mixed, and a stirrer element 'I in said vessel and rotated or spun by the means 5.

having a stator 8 formed with an annular chamber 9, an impeller Il! in said chamber and provided with impeller vanes II, and a magnet I2 driven by the impeller and connected thereto through the medium of a central stud I3. The stator is closed by a bottom plate I4 to thereby enclose the chamber 9. A water inlet I5 is tangentially provided on the stator to direct a stream for impingement against the vanes I I and thereby drive the impeller I0.

In its present form, the stator 8, in its upper part, is formed with flat-topped ns or the like I6 generally radially arranged lto form a support surface for the vessel 6 with a minimum of physical contact therewith. Said fins arev terminated short of the center of the stator to provide a cavity or housing I1 in which the rotating magnet I2 is housed. A bushing I8 is ilxedly carriedv in the stator for the stud I3 which is fixed with the impeller. A water .outlet for the motor is provided in the usual manner.

Inasmuch as it is desired to transmit little or .no heat to the vessel 6, the means 5, or at least the parts 8, III and I4, is formed of heat insulating material such as plastics. Further, any slight heat rise in these parts is dissipated by the generous surfaces of the fins I6 and, therefore, there is little or no heat transmission from the means 5 to the vessel E. The water in the motor rather acts to cool the device and the presence oi said water serves as a safety factor in this regard.

The magnet I2 may be of the permanent type, as shown, or may be an electro-magnet. As preferred, the poles thereof are directed to terminate just short thereby clear the bottom of the vessel 6.

The vessel 6 may be of any desired form but should have a generally flat bottom I9. An airtight closure 26 for the vessel is provided for the purpose above indicated.

The stirrer element 1 is of novel form to insure its central position in the bottom of the vessel and obviate eccentric disposition thereof during operation. As shown, said element is formed with a spherical central part 2 I, smaller spherical ends or poles 22, and connecting cylindrical portions 23. The element "I is formed of magnetic or magnetizabley material suitably coated or plated to resist corrosion. In practice, it is dropped to the bottom of the vessel and becomes aligned by magnet force with the poles of the magnet I2, as shown. It will be noted that the stirrer element assumes a titlted position when at rest but levels oir under the inuence of the magnetic The motive means 5 is shown as a water motor Il ilux lines of the magnet I2 and freely spins thereoi the upper edges of the fins IB and The improved features of the device resides l in the provision of motive means which generates little or no heat, in providing said means with .non-heat-conducting elements. and forming said elements with heat dissipating portions, in providing an improved stirrer element, and providing for the exclusion of air from the solution being mixed.

Other motive means such as electric motors, may be employed, provided the foregoing features are embodied in the structure.

While I have illustrated and described what I now regard as the preferred embodiment of my invention, the construction is, of course, subject to modifications without departing from the spirit and scope of my invention. -I, therefore, do not wish to restrict myself to the particular form of construction illustrated and described, but desire to avail myself of all modifications that may fall within the scope vof the appended claims.

Having thus described my invention,` what I claim and desire to secure lby Letters Patent is:

1. A magnetic mixer comprising motive means hamg a casing formed with heat dissipating portions and operated by liquid acting to adsorb heat generated by the motive means, a liquid containing vessel engaged with said heat dissipating portions, a magnet driven by said motive means, and a stirrer element resting on the bottomI of said vessel and magnetically associated with the magnet.

2. A magnetic mixer comprising motive means having a casing formed with heat dissipating portions, a liquid containing vessel engaged with said heat dissipating portions, a magnet driven by said motive means, and a stirrer element resting on the bottom of said vessel and magnetically associated with the magnet,l said stirrer element in operation having only point contact with the vessel.

3. A mixing machine comprising motive means having an upper cavity, a' magnet housed in said cavity and having upwardly directed poles and mounted to spin on a vertical axis, heat dissipating fins surrounding said cavity, a vessel re-i movably supported on the fins above the magnet. an air-tight removable closure for the vessel, and a magnetic stirrer element resting on the bottom of said vessel and magnetically rotated by the magnet.

4. A mixing machine comprising motive means having an upper cavity, a magnet housed in said cavity and having upwardly directed poles and mounted to spin on a vertical axis, heat dissipating fins surrounding said cavity, a vessel removably supported on the ns above the magnet, an air-tight removable closure for the vessel, and a magnetic stirrer element resting on the bottom of said vessel and magnetically rotated by the magnet, said stirrer comprising an elongated element having end magnetic poles and a central part larger than said poles and formed to have only point contact with the vessel bottom.

HARRY HERBERT NEAL.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS Number 

